Sen. Robert Byrd was taken to the hospital Tuesday morning after he fell in his home in an incident not deemed serious, his spokesman said.

Ambulances and fire trucks raced to the home of the 91-year-old West Virginia Democrat, the longest-serving senator in U.S. history. He was taken to a hospital but has not been admitted.

"Byrd apparently stood up too fast this morning in his home and fell down," Byrd spokesman Jesses Jacobs said. "To err on the side of caution, his caregiver call an ambulance. He was taken to the hospital where he is currently being checked out. At this point in time there is no indication that he will be admitted."

Byrd has been mostly absent from the Senate this year. He was hospitalized in May and June with serious infections. But he returned to the Senate in July to vote and earlier this month, he paid tribute to the late Sen. Ted Kennedy, who died in August.